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The California Carbon Report

Analysis of Embodied and Operational Carbon Impacts of 30 Buildings

The California Carbon Report is the first in a series of reports to be released as part of the multi-year CLF WBLCA Benchmarking Study (v2).

À propos

Actors in the built environment are promoting strategies targeted at reducing the environmental impacts of buildings. Many government agencies, design companies, builders, and developers have proposed voluntary net-zero commitments to drive change across the sector. Similarly, policymakers at both the state and national levels have been passing successful legislation to achieve mandatory emissions reductions, and many of these policies rely heavily on building-related decarbonization. Though all of these commitments and policies vary in their scopes and ambition levels, they all ultimately seek to reduce GHG emissions in alignment with Paris Agreement targets. Still, building decarbonization at scale has continued to prove challenging.

In this study, we investigated the use of whole life carbon assessment (WLCA) through a sample of 30 new construction building projects located in the State of California that were sourced from design practitioners as part of the CLF WBLCA Benchmark Study (v2). California was chosen for this preliminary study owing to its unique climate, large population, geographic size, rapidly decarbonizing electrical grid, ambitious climate targets, and quickly evolving policy landscape. By conducting this analysis, we sought to answer the following questions:

  • What is the projected balance of emissions between embodied and operational carbon over time for a sample of new buildings in California?
  • What are reasonable estimates of embodied and operational carbon intensities for the buildings analyzed?
  • What are the most significant contributors to embodied carbon impacts from different buildings’ scopes, elements, or materials?
  • What are the current gaps and challenges within industry practices toward developing comprehensive whole life carbon assessments?
  • How do the results vary based on changes to LCA methods and assumptions?

Auteurs

The research team from the Carbon Leadership Forum at the University of Washington College of Built Environments and the University of California Berkeley Center for the Built Environment:

  • Brad Benke, Researcher, Carbon Leadership Forum, University of Washington
  • Matt Roberts, Postdoctoral Researcher, Center for the Built Environment, University of California Berkeley
  • Yang Shen, Researcher, Carbon Leadership Forum, University of Washington
  • Steph Carlisle, Researcher, Carbon Leadership Forum, University of Washington
  • Mel Chafart, Researcher, Carbon Leadership Forum, University of Washington
  • Kate Simonen, Executive Director, Carbon Leadership Forum, University of Washington

Les contributions de l'auteur: Writing – original draft: B.B., M.R., and Y.S.; Writing – review and editing: B.B., M.R., Y.S., S.C., K.S., and M.C.; Conceptualization: K.S.; Methodology: B.B., M.R., Y.S., S.C., and K.S.; Data curation: M.C., B.B., Y.S., and M.R.; Formal analysis: Y.S. and B.B.; Visualization and Graphics: Y.S., B.B., and M.R.

Publié

May 2024

Remerciements

The research team would like to thank the Alfred P. Sloan Foundation, the ClimateWorks Foundation, and the Breakthrough Energy Foundation for supporting this research project.

Thank you to the data contributors of this study who provided substantial time and effort in submitting building project data for this report and sharing feedback with the research team:

Thank you to the CLF WBLCA Benchmark Study (v2) pilot phase participants who helped test and inform the data collection methods used for this study:

Additionally, thank you to the research staff that engaged with this project during its initiation, helped develop background research for its execution, and/or provided technical review:

  • Milad Ashtiani, Researcher, Carbon Leadership Forum, University of Washington
  • Allison Hyatt, (former) Researcher, Carbon Leadership Forum, University of Washington
  • Fiona Greer, Postdoctoral Researcher, Department of Civil and Environmental Engineering, University of California, Berkeley

droits d'auteur

The California Carbon Report: An Analysis of the Embodied and Operational Carbon Impacts of 30 Buildings is licensed under a Creative Commons Attribution 4.0 International Licence.

Webinar Recording

In this recorded webinar, the research team from the report shares details about the methodology used, additional findings, and how this research can support the design and policy communities toward decarbonizing real-world buildings. You can view the recording below, or by following this Youtube link.

Citation

Benke, B., Roberts, M., Shen, Y., Carlisle, S., Chafart, M., and Simonen, K. (2024). The California Carbon Report: An Analysis of the Embodied and Operational Carbon Impacts of 30 Buildings. Carbon Leadership Forum, University of Washington. Seattle, WA. http://hdl.handle.net/1773/51287.

Rapport complet

Citation

Benke, B., Roberts, M., Lewis, M., Shen, Y., Carlisle, S., Chafart, M., and Simonen, K. (2024). The California Carbon Report: Six Key Takeaways for Policymakers. Carbon Leadership Forum, University of Washington. Seattle, WA. http://hdl.handle.net/1773/51415

Policymaker Summary

Bibliothèque de ressources

Reclaimed and Reused: Recommended LCA Modeling Guidance to Support EPDs for Reused Construction Materials

Material reuse is one strategy for reducing the embodied carbon of construction. While the preparation of previously used materials for reuse has an environmental impact, it avoids many of the resource extraction and manufacturing impacts of building with newly manufactured products. Given the amount of demolition and deconstruction across North America (and beyond), there is a vast potential for material reuse to expand in scale. However, barriers to material reuse scaling exist.

DEQ Low Embodied Carbon Housing Program: Roadmap to Success

Embodied Carbon Pathways to 2050 for the United States, a collaboration between the Carbon Leadership Forum (CLF), RMI, and the University of Washington (UW) Life Cycle Lab, provides an assessment of embodied carbon from US construction materials and explores pathways to align with a 1.5°C global warming limit.

International Embodied Carbon Data Availability: A Review of Environmental Product Declaration (EPD) Availability in Europe, China, and Australia

CLF completed a landscape analysis of product-level embodied carbon data availability in regions outside North America with the goals of: (i) understanding how LCA/EPD data availability varies globally; (ii) informing where targeted initiatives are needed to increase the availability of data; and (iii) determining whether adequate EPD data exists to develop CLF Material Baselines outside North America. This report summarizes our findings and provides initial insights into what data is available to inform low-carbon procurement efforts in Australia, China, and Europe.

The CLF Benchmark Explorer

Emissions from the operations of buildings and infrastructure are significant, well-understood contributors to national and global greenhouse gas emissions. However, the contribution of embodied carbon—emissions associated with the manufacturing, transportation, installation, maintenance, and disposal of construction materials across the life cycle of a building or asset—is neglected by comparison. Even at the global level, embodied carbon estimates are typically based on manufacturing emissions from the production of a handful of the highest-impact materials (e.g. concrete, steel, aluminum, and wood).

Embodied Carbon Pathways to 2050 for the United States

Embodied Carbon Pathways to 2050 for the United States, a collaboration between the Carbon Leadership Forum (CLF), RMI, and the University of Washington (UW) Life Cycle Lab, provides an assessment of embodied carbon from US construction materials and explores pathways to align with a 1.5°C global warming limit.

Washington State Carbon Emissions Estimation: 2025 – 2050

Emissions from the operations of buildings and infrastructure are significant, well-understood contributors to national and global greenhouse gas emissions. However, the contribution of embodied carbon—emissions associated with the manufacturing, transportation, installation, maintenance, and disposal of construction materials across the life cycle of a building or asset—is neglected by comparison. Even at the global level, embodied carbon estimates are typically based on manufacturing emissions from the production of a handful of the highest-impact materials (e.g. concrete, steel, aluminum, and wood).

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